Powerful key to a finished product: batteries for pacemakers
Powerful key to a finished product: batteries for pacemakers
Interview with Dr. Tim Traulsen, Managing Director, LITRONIK Batterietechnologie GmbH
When the heart skips a beat, cardiac pacemakers can help to restore the heart's rhythm. Batteries deliver the needed power. As part of the finished product, they play an important role because their feasible size and characteristics must already be considered during the implant planning process.
Dr. Tim Traulsen, Managing Director, LITRONIK Batterietechnologie GmbH
In this interview with COMPAMED-tradefair.com, Dr. Tim Traulsen describes the criteria batteries for pacemakers must meet, explains the role they play in the development process of an implant and reveals the impact of the current miniaturization trend on this field.
Dr. Traulsen, pacemakers primarily use your high energy batteries with lithium-iodide technology and your medium-rate batteries with lithium-manganese dioxide technology. How does each of these battery technologies work?
Dr. Tim Traulsen: Lithium-iodine batteries have been the most common type of battery used in pacemakers for many years. They contain a special form of iodine that is processed with metallic lithium. The produced electricity is used for the pacemaker. The advantage of lithium-iodine batteries is that they are quite inexpensive to produce and that they offer a long lifespan and reliability. The technology is safe and has been well developed over many years. This type of battery is "fully solid", which means these are solid-state batteries with no liquid components. The drawback of lithium-iodine batteries is that they only deliver small amounts of currents in the microampere range – which is generally enough energy for a pacemaker. However, if the pacemaker is designed to accommodate advanced features such as telemetry for the recording of data, the capacity of lithium-iodine batteries is not sufficient.
In this case, you need battery types that are capable of higher current pulses. This is where other electrochemical systems – such as lithium-manganese dioxide batteries- are better suited. Their capacity is comparable but they ensure a higher rate discharge capability. That being said, they are also more complex, which makes their production more intricate and more expensive.
Which requirements do batteries for pacemakers generally have to meet?
Traulsen: Today's manufacturers aim to make implants as small as possible. This is a key factor for patients because it impacts the implantation process and subsequent comfort once the implant has been placed inside the body. A smaller implant means a less invasive procedure and less discomfort for patients due to the device. In other words, batteries should have a high capacity while being as small as possible and guarantee a long lifespan of the end device. Other essential aspects include the quality and reliability of cells. They must meet the highest expectations and standards. After all, pacemakers are lifesaving devices. That's why batteries must be reliable during the lifespan of the implant and guarantee uninterrupted patient care. A combination of reliability and a high energy density per unit volume is vital. Batteries are optimized based on these two main criteria.
You also tailor your products to each company. Which OEM services do you offer for pacemakers to customize your electronic modules for each customer?
Traulsen: We assist our customers with battery design and layout. Pacemaker manufacturers typically already have a general idea of the size and shape of battery they need. In many cases, this initial concept just needs some tweaking. We consult with our customers to achieve the optimal geometry for their application – as it pertains to size, thickness, and shape of the batteries. The contact options of the battery and circuit must also be well designed. There were different technical implementations in the past. We recommend the best contact options for our customers’ applications. There are flat contacts or so-called pins – those are needle-shaped contacts.
Our consulting services also include test programs that are needed at a later point. Together with the customer, we review the verifications that must be conducted. They make it possible to generate the required documents the customer needs to submit their medical device to the regulatory agency for approval. When manufacturers produce an implant, they must submit extensive documentation –including risk assessments and technical verification of the medical device and all of its components. Needless to say, the battery plays an important role in all this.
The battery is the largest component in most implants.
What are the current medical device trends?
Traulsen: A general trend we see is definitely the miniaturization of implants. Devices have become smaller with each generation for several years. One significant effect of miniaturization is a lower overall power consumption in circuits. From one generation to the next, the base current needed to run the device has been reduced thanks to improved semiconductors and better-integrated circuits. This permits longer lifespans despite increasingly smaller batteries. What's more, battery technology is also continually improved. The energy density is higher despite their shrinking size. The combination of these two trends results in ever-smaller implants.
One example of miniaturized implants – and also batteries – are sensors placed inside the body. There are various new technology trends in the field of neurostimulation, for example, which in turn make specific demands on batteries.
To meet the requirements of our customers in this area, we offer battery housings made of stainless steel and biocompatible titanium. Thanks to these materials, batteries can also be implanted directly into the body.
In your opinion, what role do batteries play as part of the finished product?
Traulsen: That's a very important question. The battery is the largest component in most implants. That's also why it plays a decisive role in terms of the final size and volume of the implant. Needless to say, it also has a significant impact on the lifespan, making it one of the most important components for implant manufacturers. If a manufacturer wants to end up with an excellent product, he must have the right battery. This is also reflected in the fact that as a battery manufacturer, we are typically included very early in the development process. Without batteries, other development concepts such as circuits and firmware cannot be managed in time. The battery performance data is also essential to validate implants. This makes the battery a key component that needs to be available in time to produce a pacemaker and ensure a successful process.
The article was written by Julia Unverzagt and translated from German by Elena O'Meara. COMPAMED-tradefair.com